# score= eval(input("请输入成绩分数:"))
# if score<60
#     print("成绩不合格")
# if 60 < = score < 80
#     print("成绩一般")
# if 80 < = score < = 90
#     print("成绩良好")
# if 90 < score < = 100
#     print ("成绩优秀")
#
# 单分支if语句
# 函数的功能：将字符串str当成有效的表达式来求值并返回计算结果。
# score = eval(input('请输入成绩分数:'))
# if score >= 60:
#     print("成绩已合格")
#
# 分别输入58 75 87 100进行测试 60 80 90 100
# score = eval(inout('请输入成绩分数:'))
# if score < 60:
#     print("成绩不合格")
# if 60<= score < 80:
#     print("成绩一般")
# if 80 <= score <= 90:
#     print("成绩良好")
# if 90< score <= 100:
#     print("成绩优秀")
#
# 嵌套if分别输入 88 89进行测试
# score = eval(input('请输入成绩分数'))
# if 60 <= score:
#     print("成绩已合格")
#     if 90 < score <= 100:
#         print("成绩优秀")
#
# 双分支：if-else
# score=eval(input("请输入成绩分数"))
# if score>60:
#     print("成绩及格")
# else:
#     if score<60:
#         print("成绩不及格")

# score=eval(input('请输入成绩分数'))
# if score>=60:
#     print('成绩及格')
#     if score>=90:
#         print("成绩很好")
#     else:
#         print("成绩一般")

# if-else语句中嵌套if-else
# score=eval(input("请输入成绩分数:"))
# if score>=60:
#     print('成绩及格')
#     if score>=90:
#         print('成绩很好')
#     else:
#         print('成绩一般')
# else:
#     print('成绩不及格')
#     if score<30:
#         print('成绩极差')
#     else:
#         print('成绩较差')
# 多分支结构：if-elif-else
# score =eval(input('请输入一个成绩分数:'))
# if score>=90:
#     print('成绩优秀')
# elif sore>=80:
#     print('成绩良好')
# elif sore>=70:
#     print('成绩中等')
# elif score>=60:
#     print('成绩较好')
# else:
#     print('成绩不及格')

# 课堂练习
year =eval(input('输入一个年份'))
if((year%4==0 and year%100!=0)or year%400==0):
    print(year,'是闰年')
else:
    print(year,'不是闰年')

    
# 条件循环：while
# a=1
# while a<=12:
#     print("今天是",a)
#     a +=1

# n=1
# sum=0
# while n <=100:
#     sum = sum+n
#     n=n+1
#     # print(sum)
# print(sum)

# 遍历循环：for
# for i in ['1,3,5,7']:
#     print('今天是星期', i)

# range函数
# for i in range(1,10,2):
#     print(i)


# for i in range(1,6):
#     print('上班时间为周:',1)
#     for t in range(9,18):
#         print('时间段为:',t,end="")
#     print()

# 嵌套循环
# i=1
# while i<=5:
#     print('上班时间为:',i)
#     i=i+1
#     t=9
#     while t<=17:
#         print('时间段为:',t, end="")
#         t=t+1
#     print()

# 用while循环实现99乘法表
# i=1
# while i<=9:
#     j=1
#     while j<=1:
#         print('%d*%d=%d'%(j,i,j*i),end="")
#         j=j+1
#     print()
#     i=i+1

# 用for循环实现99乘法
# for i in range(1,10):
#     for j in range(1,i+1):
#         print('%d*%d=%d'%(j,i,j*i),end="")
#         print()

# 10月29日
# 用while中使用break跳出循环
# i=0
# while i<=5:
#     i+=1
#     print('星期为:',i)
#     if i==3:
#         break

# i = 0
# while i<=5:
#     if i ==3:
#         break
#     print('星期为:',i)
#     i+=1

# for循环中使用break语句
# for i in range(1,6):
#     print("星期",i)
#     if i ==3:
#         break

# for i in range(1,6):
#     if i ==3:
#         break
#     print("星期",i)



 # while循环中使用continue语句
# i=0
# while i<5:
#     i=i+1
#     if i ==4:
#         continue
#     print("星期",i)

# for循环中使用continue语句
# for i in range(1,6):
#     if i ==4:
#         continue
#     print("星期",i)